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PAULA ZAHN, CNN ANCHOR: Our top story tonight takes us about 300 miles northwest of here to Modesto, California. That is where lawyers for Scott Peterson suffered a bit of a defeat today. They hoped to find a link between the death of a pregnant woman in San Francisco and that of Laci Peterson and, in the process, exonerate their client. That may be harder to do now. David Mattingly joins us live from Modesto with the very latest on that.

Good evening, David.

DAVID MATTINGLY, CNN CORRESPONDENT: Good evening, Paula.

You are correct, a bit of a setback for Scott Peterson's defense team today. They had been at odds with investigators from the San Francisco Police Department over access to their records, a file of an unsolved murder case that they had there. The attorneys had wanted to find out if there were any similarities between the murder of Laci Peterson and the murder of Evelyn Hernandez. She was the other pregnant woman whose body was found in San Francisco Bay, that a year ago.

San Francisco police, however, said that is where the similarities between those two cases ended and that to open up this case to the defense team would be to cause problems for their investigation. Well, today, the judge agreed. And the attorneys will not be allowed to find out what kind of evidence police have gathered.

One of the other big issues that they tackled today had to do with the wiretap phone calls between reporters and Scott Peterson. The judge today did say that reporters will be allowed to listen to their own conversations that were recorded with Scott Peterson. It is, however, not known what impact or what significance this has on the case at this point -- Paula.

ZAHN: David Mattingly, thanks so much for that update. Appreciate it.

Today's ruling is somewhat of a setback to Scott Peterson's defense. Where do they go from here?

I'm joined now by Kimberly Guilfoyle Newsom, assistant district attorney in San Francisco. Thanks for joining us. Good to be on the same coast as you for a change.

NEWSOM: Well, I think it is a setback, because, again, they were trying to establish some credibility here and suggest that someone other than Scott Peterson is responsible for Laci Peterson's death, alleging some kind of serial killer might be out there. And they failed on all grounds.

They only were able to gain access to an autopsy report that is public record. So, again, it's a poor showing for the defense, but, again, a smart move by Mark Geragos to make this request. But these two cases really have no similarities, other than the fact that both women were found in the bay. There is a logical other suspect in the Evelyn Hernandez case that the police are looking at. And it would compromise the integrity of that investigation if they were to turn over their investigatory file.

ZAHN: So you have the judge calling that information highly speculative. From your point of view, why is it that? Why shouldn't they be entitled to that evidence. Isn't it kind of ironic that you would have two pregnant women in the late stages of pregnancy wash up on San Francisco Bay's shores?

NEWSOM: It's an excellent question.

At first blush, it appears that there are similarities: both eight months pregnant, both in this same area. However, the bodies were found quite a far distance apart. In addition to that, referring to the Evelyn Hernandez case, her wallet was actually found at the place of employment, a secondary place of employment of her boyfriend, who, at the time, unbeknownst to Evelyn Hernandez, was married to another woman.

And Evelyn was carrying his child. So, again, speaking, he has not been arrested or charged in that case. He is the logical suspect that they're looking at in that particular scenario. You would have to believe that there is a serial killer out there conspiring to set up Scott Peterson and, separately, Evelyn Hernandez's boyfriend by, one, dumping Laci Peterson's body in the bay where Scott Peterson presented his alibi, and, two, by suggesting that this -- quote, unquote -- "serial killer" placed Evelyn Hernandez's wallet at Herman Aguilera's place of business.

Those are both unlikely, illogical scenarios. And, again, the defense grasping at straws with -- and the brown van, satanic cult theories, and now this one.

ZAHN: Well, as a prosecutor, you certainly understand the strategy Mr. Geragos is using here, but this is not the first time one of his theories has been shot down. Are we to read anything into that?

NEWSOM: Well, I think, again, your potential jury poll is out there and they're listening and paying attention. At a certain time point, you start to lose credibility and integrity with the potential jury pool, because, when you come up with theories that the prosecution is able to shoot down, then it points to one other conclusion, which is that Scott Peterson would be the person responsible for this offense.

ZAHN: And what does it mean that the prosecution is going to now be able to listen to some of these 176 wiretaps? Is it true that a lot of these wiretaps are nothing more than reporters begging for interviews with him?

NEWSOM: Well, it certainly will be interesting. And I'm sure a lot of people will be reporting and writing about the begging and pleading going on. So we'll see if some people are hiding out from embarrassment.

But, other than that, maybe there will be evidence that will be incriminating against Scott Peterson. It's certainly fair that the judge, this early in the proceedings, is allowing the prosecution to have access -- and the defense -- to that evidence. So, interesting that, if it had occurred further along in the proceedings, perhaps right before trial, the judge could have precluded the prosecution, through their own incompetence, from finding this information out earlier, could have precluded them from using it and presenting it in front of a jury.

And if there was compelling evidence there, they would have really been damaged.

ZAHN: Kimberly Guilfoyle Newsom, nice to have you with us tonight. Thanks so much for your insights.

NEWSOM: Thanks so much, Paula.

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